<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <div>123
        <b>555</b>
    </div>
    <style>
    div{
        border-style: solid;
    }
    div{
        border-style: solid;
        border-width: 10px;
        border-color: red;
    }
    div{
        border-top: solid;
        border-top: 10px;
        border-top: red;
    }
    div{
        border: 10px solid red;
    }
    div{
        border: 10px solid red;
        border-radius: 10px 20px 30px 40px;
    }
    /* div{
        background-color: silver;
    } */
    div b{
        background-color: transparent;
    }
    body{
        background-image: url(loading.gif);
    }
    div{
        background-image: none;
    }
    body{
        background-image: url(loading.gif);
        background-repeat: no-repeat;
    }
    div{
        width: 400px;
        height: 300px;
        border: 10px dashed red;
        padding: 50px;
        background-image: url(img.png);
        background-repeat: no-repeat;
        background-origin: content-box;
    }
    </style>
</body>
</html>